1. Technical Field
The present invention may be applied to a case in which in an optical disc apparatus and a magnetic disc apparatus, for example, such as a hard disc apparatus for recording a video data and the like, an exchange allocating process is carried out to thereby reserve an access having a high reliability.
2. Background Art
Conventionally, as an apparatus for recording an audio data and a video data (hereafter, referred to as an AV data), a video tape recorder using a magnetic tape as a recording medium has been widely used. Such a video tape recorder is configured such that the AV data inputted in time series is divided by a field or frame unit of the video data, and obliquely recorded on the magnetic tape.
On the other hand, a personal computer is configured so as to use a hard disc apparatus and then record an application program and the like. Then, the hard disc apparatus has been sharply made denser and smaller.
In such a hard disc apparatus, it is connected to a personal computer through an interface, such as ATA (AT Attachment), SCSI (Small Computer System Interface) or the like, and used as a peripheral of the personal computer, and the data is managed at a sector unit, and an exchanging process of a defective region, an error correcting process, a retrying process and the like are carried out to thereby enable the data recorded on the hard disc to be reproduced at an extremely high accuracy.
With regard to the exchanging process of the defective region among them, the hard disc apparatus is configured so as to carry out two kinds of processes so that it copes with the defect of the hard disc. That is, in the defects induced in the hard disc, there are a primary defect and a secondary defect. Among them, the primary defect is the defect already induced at a time of manufacturing and shipping, and the secondary defect is induced because of aged deterioration.
The hard disc apparatus carries out a verifying process at the time of the manufacturing to detect the defective region caused by the primary defect at a sector unit and then register a physical address of this detected defective sector in a primary defect list. The hard disc apparatus, when a write command or a read command is inputted from a host computer, converts a logical address set for this command into the physical address to then access the hard disc. At this time, the hard disc apparatus converts the logical address into the physical address by referring to the primary defect list and thereby jumping over the defective sector and then carrying out the access (a so-called slipping process). Thus, the hard disc apparatus is configured so as to cope with the primary defect. This process is characterized in that since it is the process for jumping over the defective sector and carrying out only the access, the change in data transfer speed caused by the presence or absence of the defective sector is slight.
On the other hand, the hard disc apparatus copes with the secondary defect by carrying out an exchange allocating process. Here, the exchange allocating process is the process for allocating the defective sector to a sector of an change region that is a region for a spare set on an information recording surface. By the way, such a secondary defect is detected by carrying out a writing and verifying process at a time of writing, or a process at a time of reading out.
That is, the hard disc apparatus carries out this exchanging process, for example, in accordance with a read verify command (a command to carry out only an operation for verifying data without carrying out data transfer to a host) from a host apparatus. The hard disc apparatus, in this exchanging process, firstly detects an occurrence of an error in data portion and an ID portion at each sector. Actually, the hard disc apparatus establishes a standard for an ID detector in relation to a process for detecting those errors, an ECC error detecting process, a retrying process and the like. On the basis of this standard, it judges a reproduction result at the sector unit to thereby detect a sector that is poor in reliability. The hard disc apparatus, when detecting such a sector having the poor reliability, defines this sector as the defective sector caused by the secondary defect. The hard disc apparatus re-records the data recorded in the defective sector detected as mentioned above in a sector of an change region, and correlates the physical sector in this exchange region with the physical address of this defective sector, and then registers in a secondary defect list. The hard disc apparatus records this secondary defect list on the hard disc, and then completes the exchange allocating process.
The hard disc apparatus accesses the sector of the corresponding exchange region instead of the defective sector, in accordance with this secondary defect list if such an exchange allocating process is carried out, and thereby reserves the reliability. Thus, when the hard disc apparatus reproduces continuous sectors, if a part of the continuous sectors is the defective sector, it reproduces the continuous sectors immediately before the defective sector, and after that, it carries out a seeking operation and reproduces the corresponding sector of the exchange region (implying the exchange sector), and then seeks the sector subsequent to the original defective sector, and reproduces this subsequent sector. Hence, in the case of this exchange allocating process, it has a problem that a drop in the data transfer speed is remarkable, as compared with the case of the slipping process.
FIG. 1 is a block diagram showing the configuration of the hard disc apparatus, with regard to the reading out process when such an exchange allocating process is carried out. By the way, in the hard disc apparatus 1, an interface control circuit (IF control) 2 is a host interface, and it receives data used for writing and a command from a host apparatus, and outputs the data based on an access and a status corresponding to this command.
A recording/reproducing system 3 is provided with a read write data channel with regard to a signal process of a magnetic head and a servo system serving as a driving system. The recording/reproducing system 3 accesses a hard disc 5 in accordance with a physical address outputted by a hard disc control circuit 4, and drives the magnetic head in accordance with data outputted from a buffer memory 6, and then records this data on the hard disc 5. Further, at a time of reading out, it performs a signal process on an output signal of the magnetic head, and reproduces the data recorded on the hard disc 5, and then outputs to the buffer memory 6 or the hard disc control circuit 4. The recording/reproducing system 3 carries out this process, and reproduces a secondary defect list LST recorded on an inner circumference of the hard disc 5, when a power supply is turned on, and then reports to the hard disc control circuit 4.
The buffer memory 6 tentatively stores the output data of the recording/reproducing system 3, and carries out an error correcting process and the like, and then outputs through a host interface 2 to a host apparatus. By the way, at a time of recording, reversely to the above-mentioned case, the buffer memory 6 transiently stores the data outputted from the host apparatus through the host interface 2, and outputs to the recording/reproducing system 3.
The hard disc control circuit 4 analyzes the command inputted from the host interface 2, and controls the entire operation in the hard disc apparatus 1. In the process when the power supply is turned on, the hard disc control circuit 4 controls the recording/reproducing system 3, and instructs it to reproduce the secondary defect list LST, and then obtains the secondary defect list LST from the recording/reproducing system 3. The hard disc control circuit 4 stores this secondary defect list LST in a built-in memory.
In the condition that the secondary defect list LST is stored as mentioned above, the hard disc control circuit 4, when a read command is inputted through the host interface 2, converts a logical address added to this command into a physical address through a process in an address converter 4A, and instructs the recording/reproducing system 3 to carry out the reproduction based on this physical address. At this time, the hard disc control circuit 4 generates the physical address so as to access the corresponding exchange sector, for the defective sector, in accordance with the secondary defect list LST.
That is, FIG. 2 is a flowchart showing processing procedure of the hard disc control circuit 4 in relation to the read command. The hard disc control circuit 4, when the read command is inputted from the host apparatus, proceeds from step SP1 to step SP2. Then, it receives this read command, and converts a logical address based on a parameter set for this read command into a physical address of the hard disc 5, at a next step SP3.
In succession, at step SP4, the hard disc control circuit 4 refers to the secondary defect list LST stored in accordance with the physical address converted as mentioned above, and judges whether or not the sector based on the access includes the secondary defective sector, at a next step SP5. Here, if the sector based on the access does not include the secondary defective sector, the hard disc control circuit 4 proceeds to step SP6, and controls the entire operation in accordance with the thus-converted physical address, and then reads out the data instructed by the host apparatus from the hard disc 5, for the sector of this physical address.
Moreover, the hard disc control circuit 4 stores the data read out as mentioned above, in the buffer memory 6 at a next step SP7. The hard disc control circuit 4 outputs the data stored in the buffer memory 6 to the host apparatus at a next step SP8, and ends this processing procedure at step SP9.
On the other hand, if the sector based on the access includes the secondary defective sector, the hard disc control circuit 4 proceeds to the step SP5 to step SP10. Here, the hard disc control circuit 4 converts the physical address of the defective sector into the physical address of the exchange sector. Moreover, the hard disc control circuit 4 instructs it to access the hard disc 5 in accordance with the physical address including the physical address of the exchange sector as mentioned above, at a next step SP11.
Consequently, in the hard disc apparatus 1, if the access based on this read command includes the defective sector, the continuous sectors immediately before the defective sector are reproduced to then access the exchange sector at the defective sector and obtain a reproduction data, and after that, the sector subsequent to the defective sector is accessed to obtain the reproduction data. The hard disc control circuit 4, when reproducing the data from the hard disc 5 as mentioned above, proceeds to the step SP7, and records in a buffer memory 20, and then outputs to the host apparatus at the next step SP8, and ends this processing procedure.
Consequently, the hard disc apparatus is configured so as to seek the magnetic head before and after the defective sector, in accessing the continuous sectors, if such an exchange allocating process is carried out. Thus, in the hard disc apparatus, respective seeking times and rotation waiting times for a next sector are induced before and after this defective sector, which results in a case that it is difficult to reproduce the continuous data.
Incidentally, even in recording the AV data, it may be considered to apply the hard disc apparatus and thereby fabricate a small recorder that may attain the recording of a long time, instead of the video tape recorder. In this case, in the hard disc apparatus, it is required that the continuity of the data has priority over the reliability of the data.
However, in the hard disc apparatus, there may be a fear that it is difficult to reproduce the continuous data by the execution of the exchange allocating process because of the above-mentioned secondary defect. For this reason, if the conventional hard disc apparatus is merely applied to the recording/reproducing of the AV data, this application may lead to the fear of the occurrence of the fatal picture defect.
As one method of solving this problem, a method of carrying out the exchange allocating process at a plurality of sector units is further proposed (a so-called linear changing method). However, the case of this method requires a large number of exchange regions, which results in a problem that the information recording surface of the hard disc may not be effectively used corresponding to it, and as well as other similar problems.